Originally posted by Asen What caps does Mr. Pass use in the original ALEPHs? Black Gates?

Thanks

I don't think Nelson cares all that much about components as long as they have decent specs, if you look at the XA200 pics he posted here it's all digikey type parts, like panasonics PP for ac coupling etc. The whole thing just naturally sounds good because the design is good. If you added black gates here and there it would probably sound sublime that's why I started the BG bulk purchase.

When looking at your PCB, it's hard not to notice that you are using very long leads to components and also dress them in a sort of plastic jacket. First of all, it is all extra work and actually it is something not desirable. Just trim them as short as possible (especially for TO-92 semis and mica caps) and don't be afraid to rest them on a board.
This is not production and you should pay different kind of attention to small details.

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The IRFP9610 has it's Drain connected to it's flange. The Drain is the center pin (I don't know the other type with an extra pin). The Drains of each differential pairs do not meet each other. The Sources do.

I don't know the insulator you use for the component leads, but using materials similar to cable insulators, I used to be able to locate the degradation in the sound quality. Disagree? Well, remove from one channel and compare. If you can't hear the improvement, don't sue me.

I also used to mount components off the board like yours. Sometimes even times longer. Especially for expensive capacitors and resistors. This is to allow for the components to migrate from PCB to PCB.

Hey, where do you get that Pass Labs' PCB? Damm, I don't have a credit card!

Using that plastic tubing over the parts leads my add some capacitance that would be undesrible in the circuit. The heatsinks are also not really needed but do look nice. I used different sinks on mine as the photo below shows......
Mark

Originally posted by Mark A. Gulbrandsen The heatsinks are also not really needed but do look nice. I used different sinks on mine as the photo below shows......

The IRF on current source passes higher current than IRF in the differential pairs, and sure will get hotter (so you may want to add heatsink here). The higher the current usually the better the performance (so you won't want to add resistance to offset the DC in current source).

MOSFET can withstand a higher temperature than it will experience here, but ("they" say) will reduce the MOSFET life. The last statement may be useless. What you may want to hear is whether such temperature (I think more than 100C) will degradate the performance to an audible degree. Because the MOSFET will be damaged or replaced long before it's usefull life anyway.